Heatsink mounting

[Toby]

So I bought a pc from pc specialist over a year ago and I decided that I needed to upgrade it. I go a 7870k to go in the
A88-xm plus that was in the computer. I in screwed the massive silver heat sink from my old processor and swapped the chips around. However when I went to put the stock heatsink that came with the processor there was no where to clip the clips on. I'm guessing that it was taken off when pc specialist built it as i have seen photos of the motherboard with them on. What can I buy that replace one of these and fit the heat sink in?
Sorry for my limited knowledge I am a bit of a scrub at this haha.

 

[beers]

Which specific 'massive silver heat sink' was it? Also, why go back to stock?

Most tower type of HSF require their own mounting brackets that generally end up removing the stock mounting plate.

 

[Toby]

So the old processor that was in there was the AMD A6-6400K with the Super Quiet 22dBA Triple Copper Heatpipe AMD CPU Cooler on top. I was going to use the stock one because I didn't know if it would work and I didn't want to risk it. Also the stock one would be easier to apply. I think I found what I might need (http://www.amazon.co.uk/Retention-Bracket-Base-Yellow-Socket/dp/B007PPEUPE) but I'm not sure. Thank again for the help